1. Field of the Invention
The present invention relates to an image forming method and an image forming apparatus, and more particularly to image formation technology in an image forming apparatus for forming a desired image on a medium by reacting an image forming liquid such as ink with a treatment liquid and fixing the image forming liquid onto the medium.
2. Description of the Related Art
In recent years, inkjet recording apparatuses have become common as image forming apparatuses which form images, such as photographic images, documents, or the like, on a medium. An inkjet recording apparatus forms a desired image on a medium by ejecting droplets of ink from nozzles, by driving ejection elements provided in the print head in accordance with data.
Depending on the type of medium and the type of ink, when the ejected ink droplets permeate into the media, bleeding or spreading of the formed dots may occur, thus leading to a marked decline in the quality of the image formed. In order to prevent image deterioration caused by bleeding or spreading of dots in this way, a system has been proposed which uses a radiation-curable ink whose curing (fixing) is promoted by the irradiation of radiation, such as ultraviolet light or an electron beam, onto the ink droplets ejected onto the media.
Japanese Patent Application Publication No. 10-287035 discloses an inkjet recording method, a recorded object, and an inkjet recording apparatus where printing is carried out by depositing a reactive solution containing a photopolymerization initiator, and an ink composition containing an acrylate monomer and an oligomer, onto a recording medium, and thereby print bleeding and print non-uniformities are suppressed so as to prevent color bleeding, which is uneven color mixing occurring at the boundary regions between the different colors used in the color inkjet recording method.
Japanese Patent Application Publication No. 2003-12971 discloses an inkjet recording method whereby printing is carried out by depositing an ink composition containing 30% to 98% (wt %: weight percentage) of a polymer compound and a coloring material, and a reactive liquid containing a polymer compound and a polymerization initiator, onto a recording medium, and thereby print bleeding and print non-uniformities are suppressed so as to prevent color bleeding, which is uneven color mixing at the boundary regions between the different colors in the color inkjet recording method.
Furthermore, Japanese Patent Application Publication No. 2000-135781 discloses an inkjet recording apparatus, an image forming method, and ink composition where at least a portion of the image is formed by mixing and curing a first ink composition and a second ink composition, in such a manner that a clear and highly detailed image can be recorded, even onto normal paper which has not received special processing.
However, according to a method whereby an ink droplet is ejected onto a treatment liquid deposited onto the media, the surface of the treatment liquid on the media onto which the ink droplets are ejected is not a completely flat surface, but rather the perimeter sections thereof in particular have a gradient, and hence the ink droplets deposited onto the treatment liquid may move due to this gradient. In this way, the dots are not formed at the prescribed positions, due to the movement of the ink arising at the perimeter sections of the treatment liquid, and this affects the quality of the image formed on the media.
Furthermore, if an organic solvent having the high boiling point is used for the solvent of the treatment liquid, then the unreacted treatment liquid which is not incorporated into the polymer compound (monomer, oligomer, or the like) in the ink, does not cure and remains on the surface of the media. Moreover, if the treatment liquid is deposited over a broader range than the ink droplet ejection range in such a manner that an ink droplet is not ejected onto the perimeter sections of the treatment liquid, then the amount of unreacted treatment liquid remaining on the surface of the media increases.
Japanese Patent Application Publications No. 10-287035, No. 2003-12971, and No. 2000-135781 do not disclose or suggest a concrete method for preventing landing interference in the case of high-speed printing. Landing interference means, for example, a phenomenon that a liquid droplet of ink moves and becomes fixed at a position different from its originally intended landing position or a phenomenon that the shape of the liquid ink droplet is deformed and disrupted, due to combination between liquid ink droplets on the surface of the recording medium, before fixing, and immediately after the ink droplets have landing on the recording medium. If landing interference occurs on the recording medium, in the cases of ink droplets of the same color, a density non-uniformity may become visible, and the line quality may decline. Furthermore, in the cases of inks of different colors, color bleeding may occur.